Oven for drying or baking molds and cores



March 16, 1954 c. F. MAYER 2,671,969

OVEN FOR DRYING 0R BAKING MoLDs AND coREs Filed Dec. 2, 1952 2Sheets-Sheet 2 jkl tlll

M) ya@ IN VEN TOR. CARL E' MA YE@ rroR/vy Patented Mar. 16, 1954 UNITEDSTATES PATENT avrete OFFICE OVEN FOR DRYING OR BAKING MOLDS AND CORES 10Claims.

Thisinvention relates, generally, to that class ing or for baking greensand molds and cores.

thereby to convert them into so-called skin dried or dry sand molds andcores.

An oven of the particular type with which my present invention isconcerned consists of an elongated structure enclosing a tunnel-likepassage that is open at its ends and through which the molds and coresare continuously moved by conveying means. Heated gaseous iiuid isconstantly circulated through a part of the oven, thereby to create aheating zone that usually occupies the greater portion of the length ofsaid passage, and wherein the molds or cores are dried or baked, while alower temperature illid. desirably atmospheric air at ambienttemperature, is impelled through an adjacent part of the oven, usuallysubstantially the remaining portion of the length of said passage,thereby to provide a cooling zone wherein the molds and cores are cooledto at least a comfortable handling temperature before leaving the oven.

Obviously, other factors remaining constant,

.it takes longer to bake molds or cores to a dry state, than it does tosurface dry them; and it takes longer to dry or bake thick wall moldsthan .those having thin walls, or 4massive cores, than those of lessbulk. Furthermore, the composition of molds and cores that are handledduring 2 a Vparticular run of the oven, may differ somewhat from thecomposition of molds and cores handled at other times, and these diversecircumstances call for heating periods of different duration in order toavoid over or under drying I or baking.

As is well known to those acquanited with the type of oven to which theinvention pertains, it has heretofore been the practice to alter thedrying or baking period by changing the speed s of the conveyor. Thispractice, however, connes the ilexibility of the oven, so to speak,solely to the variable speed of the conveyor.

It is a purpose of my invention to increase this range of iiexibility byproviding also, means for changing the length oi the heating zone. Inadjusting the oven tothe requirements of a particular run, the speed ofthe conveyor and the length of the heating zone are coordinated toaccomplish the highest rate of production with the proper degree ofdrying or baking.

In view of the various before-mentioned considerations, it is anotherobject of my invention to provide an oven of the type above describedincluding means for conveniently changing the length of the heating zoneaccording to different requirements, and. wherein the minimum lengthcooling zone resulting from the maximum extension of the heating zone issuflicient to cool the work to a handling temperature. The lengtheningof the cooling zone, on the other hand, 130 its full capacity whichresults from shortening the heating zone as much as possible has nodetrimental effect, but rather an advantageous one. In the carrying outof my invention I employ supply duct means and receiving duct means thatextend substantially the full length of the oven structure and Idesirably arrange them with the supply duct means adjacent the top ofthe oven passage and the receiving duct toward or at the bottom thereof,although my invention is not particularly limited to this arrangement.Intermediate the ends of the supply and receiving duct means areprovisions for dividing each of said duct means into sections of varyinglengths, my present preference being a plurality of dampers spaced apartalong the respective supply and receiving duct means, with thecorresponding dampers of the two duct means in substantially the samevertical plane.

It is another object of my invention t0 operatively connectcorresponding dempers of the supply and receiving duct means so thatthey may be operated in unison and so that they will open simultaneouslyand close in the same fashion.

A further object of the invention is to provide mechanism by which allof the dampers are interconnected in'such a Wag,7 that only one of theupper dampers, and the corresponding lower damper, willfbe closed at anyone time; and it is a still further object to include in said mechanismindicating means showing the length of the heating zone and the lengthof the cooling zone that results from each adjustment of said mechamsm.

These and other objects-including simplicity of structure and uniqueduct arrangement resulting in increased efciency, are attained in theembodiment of the invention illustrated in the accompanying drawings,wherein:

Fig. l represents a longitudinal section through the oven substantiallyon the line I-I of Fig. 4;

Fig. 2 is a fragmentary side elevation, on a scale twice that of l,showing the damper adjusting mechanism and the indicating means; Fig. 3is a similar view showing the opposite side of the oven and theoperative connections between the corresponding upper and lower dampers,and

Figs. 4 and 5 are transverse sections on the 3 line AA, looking in thedirection of the arrows 4, 4 and 5, 5 respectively.

In the drawings, like parts are designated by like reference charactersthroughout the several views.

The oven consists of an elongated structure, designated generally by thereference numeral I, that is made up in most part of a casing cornposedof a top wall 2, side walls 3 and 4 and end walls 5 and 6, all desirablyinsulated in the usual way, the latter walls 5 and 6 being provided withan inlet opening 'i and an outlet opening 8, respectively. This casingis supported upon a floor I6 Over a pit I I that is dened by a bottomwall I2, side walls 3a and It, and end walls 5a and 6a, said end wallsbeing spaced a substantial distance from the respective end walls 5 andE of the casing, the walls I2 and 3a to 6a' being of concrete or similarmaterial and integral with the oor Il). It is apparent from thedisclosure so far that the'walls I2, ."1a and 4a are parts of theelongated structure I that encloses-a tunnel-like passage designated A.

Supported within and transversely of the passage A, adjacent the topwall 2` and. near the respective end walls 5 and 6, are exhaust ducts I5and I6, each having branches il and I8, respectively, that. extend downalong the side walls 3V and 4 of the casing, the opposed branches of theexhaust duct I6 continuing substantially to the bottom of said walls,while those of the exhaust duct I5 stop in proximity to the lower end ofthe inlet opening 1A. Said branches are provided with inlet means orslotsv I9. Proiecting laterally from cach of the exhaust ducts it',4 andI.6, through openings in the respective walls 5 and. v,.are ductextensions that communicate, through conduits 22, with the inlets ci theshells of impellers or blowers 24, shown as driven by electric motors26. The outlets of the shells of desirably co-extensive in length. withthe supp-y fe duct 36, are auxiliary supply ducts or headers 33 thatcommunicate at intervals therealonf with the duct through cross ducts35,A any suitable number being employed. Communicatin". with anddepending from the headers 33 are drop ducts 3l that are spaced apartalong the pas,- sage A, and are provided with outlet means or openings3S. The duct 30, alone, or in combination with one or more of the ductsand headers communicating therewith, constitutes the supply duct meanshereinbefore referred to.

Situated in the lower portion of the structure I. is a receiving ductmeans, presently in the form of a continuous duct 49 that is suitablysup.- ported midway between the bottoms of the casing walls 3 and 4, andis provided throughout4 its length with inlet means or openings 4 i. Theduct 4G is shown as terminating adjacent the inlet end of the passage Ain the vertical plane of the corresponding end of the supply duct 30,and. at its opposite end it proiects between the downwardly extendingbranches I3 of the exhaust duct` I6, wherewith it communicates throughlateral ducts 42. y

The upper or supply duct means, comprising,

4 in the present instance, the supply duct 30 and headers 33, isprovided with dampers 45, and fil', that are spaced apart a substantialdistance longitudinally of said duct means. The lower or receiving ductmeans is equipped with a like number of dampers, designated 45a, 46a and41a, those of the lower series being directly below the correspondingdampers of the upper series.

While the several dampers may be equipped with individual adjustingmeans for opening and closing them, I prefer to provide operativeconnections between the corresponding upper and lower dampers so thatthey may be operated in unison and in the same manner-that is to say, sothat both will be opened or closed at the same time. The correspondingupper and lower dampers may be thought or" as a set; and it is a furtherdesire to interconnect the several sets by suitable adjusting mechanismwhereby the dampers of only one set will be closed at any one time. Tothese ends provide the damper adjusting mechanism illustrated in Fig. 2,and I operatively connect the dempers of each set by the means shown inFig. 3. Referring to the latter View, the shafts of the dampers i5 ande5, where they project beyond the wall 3, have secured to them arms 553whose distal ends are connected together by a link 5I, shown in thepresent instance as having attached thereto a weight 53. Secured to theshafts of the dampers 4l and Ma are arms 55, shown as arranged inreverse relation to the arms 5); and the arms 55 are operativelyconnected by a link 's on which is shown av weight 58. Fastened to theshafts of the dampers 46 and 45a are sprocket wheels 60 about which isengaged a chain 62.

Referring now to 2: gear quadrants 65 and 5B are fastened to the ends ofthe shafts of the respective dempers 45 and 47, where said shafts extendbeyond the wall li. These quadrants are shown as extending from theopposite sides of the shafts to that from which the arms 56 and 55proiect. Accordingly, the weight of said arms and their connecting linksand weights, tends to hold the quadrants F55 and 65 against therespective stops 68 and 63. Fastened to the corresponding end of theshaft of damper 46 is a gear segment i9. As will be noted, this segmentis in a central position when the damper 46 is closed. It will furtherbe observed that the clampers 45 and 4@ of the central set are closed.when those of the other sets are open. A bar 12 is shown as supportedalon'rside the oven wall 4 by guides or rollers i3. A rack 'M on saidbar constantly meshes with the gear segment lil. Shorter racks 'l5 andi6 on the bar 'i2 are arranged for cooperation with the respective gearquadrants and 65. A lever 'i8 is pivoted at 'i9 to the wall l and hasconnection with the bar i2 throuffh a link 230. Accordingly, when thelever is swunnr on its pivot, as by means of a handlel S2, it will movethe bar 'l2 longitudinally.

When the dampers of any one set are closed, they divide the respectivesupply and receiving duct means into so-called heating cooling sectionswhich, in turn, determine the length of the heating and cooling zones ofthe passage A. Accordingly, the length of these zones may be varied byclosing the dampers of the different sets, it being remembered that whenthe dampers of any one set are closed, those of the other sets are open.According. to the arrangement of the dempers illustrated in thedrawings, the heating zone extends from the vicinity of the inletopening -1 of the oven casing to the central set of dampers, or, inother words, to the set comprising dampers 46 and 46a. It follows,therefore, that the cooling zone extends from the vertical plane of saiddampers to near the outlet opening 8 of the oven casing.

Supported upon the oven structure I, about midway between the endsthereof, is a conventional type of heater 85, red by oil or othermedium. The inlet of the circulating space of the heater is placed incommunication with the receiving duct 4B by conduit means 88 thatextends across the top of the structure and down the opposite sidesthereof and thence inwardly through openings in the side walls 3 and 4and joins the duct 40, as best shown in Figs. l and 4. The outlet of thecirculating space of said heater is placed in communication, throughconduit means 89, with the inlet of the shell of an impeller or fandesignated 90. This impeller or fan is driven by an electric motor 9|.'I'he outlet of said shell opens through the top wall 2 into the supplyduct 30. It is evident, from the arrangement described, that when theimpeller or fan 90 is in operation, gaseous fluid will be withdrawn fromthe heating Zone of the passage A through the duct 48, duct means 38,the circulating space of the heater 85 and duet means 89 into the shell90, from which it will be expelled into the duct 38, to be distributedthroughout the heating Zone by said duct and the drop ducts 31.

Surmounting the structure I above the cooling zone is an impeller or fan95 that receives atmospheric air through a pipe 96 that is connected tothe inlet of the shell of' said impeller or fan. The outlet of saidshell has communicative connection through an opening in the top wall 2,with the section of the supply duct 30 in the cooling zone. The impelleror fan 95 is driven by a motor 98 and when in operation draws inatmospheric air and distributes it throughout the cooling zone by way ofthe section of the supply duct means situated in said zone andincluding, in the present case, the corresponding sections of theheaders 33 and the drop ducts 31 that depend therefrom. At the sametime, air is withdrawn from the cooling zone through the section of thereceiving duct 48 1ocated therein and this air is exhausted to the atfmosphere through the connections previously described, including theexhaust duct I6 and its branches I8 ,and the adjacent irnpeller orblower 24.

An endless conveyor |99, schematically illustrated in the drawings,serves to carry the Work, which may consist of molds and/or cores,continuously through the passage A, the upper, work-supporting flight ofthe conveyor entering the passage through the inlet opening 1, andleaving the passage through the outlet opening 8. The conveyor, in thepresent embodiment of the invention, consists of endless chains that areguided about pairs of large sprockets |92 and |03, mounted on shaftsthat are journaled in supports shown as located in the pit adjacent theend walls 5a and il@4 thereof. Occupying an offset of the pit is anelectic motor |85 that drives, through a change speed mechanism |86 anda chain or belt |81, the shaft to which the sprockets |13 are fastened.The work-supporting part of the conveyor may be made up of cross bars orrods that are carried by and between the opposed chains of the conveyor.Except in a broad sense, the conveyor constitutes no part of the presentinvention, and accordingly itis believed unnecessary to illustrate anddescribe, in detail, the structural features of the conveyor and itssupporting and guiding means.

In the use of the oven, the work is moved at an appropriate speedthrough the passage A by the conveyor |00, whereon it rests, and whiletraveling through the heating zone the work is subjected to the hotgaseous fluid that is blasted downwardlly and laterally against andabout the work by the duct and drop ducts 31. Said fluid is thenreturned through the section of the receiving duct that is located inthe heating zone, and through the duct means 88, to the heater 85, whereit is reheated, and from which it is conveyed by the duct means 89 tothe shell of the impeller or fan 98. Under the influence of the impelleror fan, the reheated fluid is returned to the heating zone through thesupply duct means. As the work continues on through the cooling zone,its temperature is lowered by the atmospheric air that is circulatedthrough said zone in the manner already described.

The exhaust ducts |5 and I6, with their branches, serve to arrestatmospheric air that tends to enter the oven through the openings 1 andil, and prevent escape of the gaseous fluid from the oven, which latteris laden with vapors that are driven off from the work during thetreating process.

In practice, and by way of example, the aggregate length of the heatingand cooling zones may approximate feet; and the sets of dampers may befour feet apart, with` the central set approximately 34 feet from thereceiving end of the heating zone, and, accordingly 16 feet from theexit end of the cooling zone. On this basis I have shown as applied tothe side wall 4 of the oven casing, in association with the lever 18that serves as a pointer, three index marks that have associated withthem designations showing the length of the heating zone and the lengthof the cooling zone when the lever points to any selected one of theindex marks. With the damper adjusting mechanism in the positionillustrated in Fig. 2, the dampers 46 and 46au of the middle set areclosed, while the `dampers of the other sets are open, and as aconsequence thereof the heating zone is 34 feet longand the cooling zone16 feet long, this fact being indicated by the designation 34' I-I-lf C.When the lever is swung by means of the handle 82 to the left, astheparts are viewed in Fig. 2, until said lever points to the left handindex mark, the gear quadrant will be swung through by the rack l5,which, as previously pointed out, is carried by the bar 12 which hasconnection with said lever through the link 89, thereby to close thedampers 45 and 45a. At the same time the rack 14 will swing the gearsegment 10 through 90 to open the dampers 46 and IlliaV of the middleset. The-dampers 4'! and 4l'a of the third set will remain open for thereason that, under the present circumstances,

the rack 18 will move away from the gear quadrant 68 and leave itagainst the stop 69, and the dampers 41 and 41a open. Under such anadjustment of the mechanism, the heating zone will be 30 feet long andthe cooling Zone 20 feet long, according to the designation to which thelever now points. It is evident from what has been said that when thelever is swung to its other extreme position, the dampers 41 and 4'1awill be closed, while the othersl will be open.

accises 7 This adjustment ci the. dempers will lengthen the heating zoneto 38 feetl and shorten the cooling zoneto l2 feet.

Thus the length. of the heating' zone, and consequently the effectiveduration ofV theA heating period, may be varied according to therequirements of the work being handled.

Having thus described my invention, what I claim is:

l. An elongated oven structure having an inlet opening at one end and anoutlet opening at the other and enclosing a through passage, conveying`means for continually moving work through said passage, continuoussupply duct means opening into said passage substantially throughout thelength thereof, continuous receiving duct means communicating with saidpassage approximately irorn end to end thereof., means intermediate theendsof each or" said' duct means by which the latter means may beseparated at different selected locations therealong into a heatingsection and a cooling section, communicative connections between theheating sections of the two duct means, heating and impelling means insaid communicative connections arranged to withdraw gaseous fluid fromthe through passage through the heating section of the receiving ductmeans and heat said fluid and return it to the passage through theheating section of the supply duct means, air impelling and conductingmeansfor delivering atmospheric air to the cooling section of the supplyduct means, and exhaust means in communication with the cooling sectionof the receiving duct means for withdrawing air from said passage.

2. The combination and arrangement of. parts den'ned by claim l, andadditional exhaust means communicating with the through passageimmediately adjacent each end thereof.

3. An elongated oven structure having an inlet opening at one end and anoutlet opening at the other and enclosing a through passage, conveyingmeans for continually moving Work through said passage, continuoussupply duct means opening into said passage substantially throughout thelength thereof, continuous receiving duct means communicating with saidpassage approximately from end to endv thereof, means intermediate theends 0f said duct means by which each of said duct means may' be.separated at different selected locations therealong, but substantiallycorresponding locations with respect to the other duct means, into aheating section and a cooling section, com-Y municative connectionsbetween the heating sections oi the two duct means, heating andvimpelling means in said communicative connections arranged to withdrawgaseous uid from the through passage through the heating section of thereceiving duct means and heat said uid and return it to the passagethrough the heating section o1" the supply duct means, air impelling andconducting means for delivering atmospheric air to the cooling sectionof the supply duct means, and exhaust means in communication with thecooling section of the receiving duct means for withdrawing air fromsaid passage.

4. The combination and arrangement of parts defined by claim 3, andfurther exhaust means communicating with the through passage immediatelyadj acent each end thereof'.

5. An elongated oven structure havingv an inlet opening at one end andan outlet opening at the other and enclosing a through passage, convey--ing means for continually moving work through said passage, continuoussupply duct means opening into said passage substantially throughout thelength thereof, continuous receiving duct means communicating with saidpassage approximately from end to end thereof, a series of dampers inand spaced apart longitudinally of each of said duct means forseparating the duct means into heating sections and cooling sections ofvarying lengths, respectively, means fol` opening and closing saiddampers at will, the individual dempers of the supply duct means beingin substantially the vertical plane of the corresponding dampers of thereceiving duct means, communicative connections 'between the heatingsections of the two duct means, heating and impelling means in saidcommunicative connections arranged to withdraw gaseous duid from thepassage through the heating section of the receiving duct means and heatsaid iiuid and return it to said passage through the heating section ofthe supply duct means, air impelling and conducting means for deliveringatmospheric air to the cooling section of the supply duct means, andexhaust means for withdrawing the air from the passage through thecooling section or the receiving duct means.

6. An elongated oven structure having an inlet opening at one end and anoutlet opening at the other and enclosing a through passage, conveyingmeans for continually moving work through said passage, supply ductmeans opening into said passage substantiallyl throughout the lengththereof, receiving duct means communicating with said passageapproximately from end to end thereof, a plurality of dampers in thesupply duct means and spaced apart longitudinally thereof, a similarnumber or" dempers in the receiving duct means and spaced apartlongitudinally oithe latter according to the spacing apart of the formerdempers, each damper associated with the supply duct means being insubstantially the same vertical plane as the corresponding damper of thereceiving duct means and constituting therewith a set, operativeconnections between the dempers of each set whereby they are caused tomove simultaneously and in substantially like manner, the dampers ofeach duct means being intermediate the ends of said means and beingadaptedv to divide the duct means into a heating section and a coolingsection, communicative connections between the heating sections of thetwo duct means, heating and impelling means in said communicativeconnections arranged to Withdraw gaseous fluid from said passage throughthe heating section of the receiving duct means and heat said fluid andreturn it to the passage through the heating section of the supply ductmeans, air impelling conducting means for delivering atmospheric air tothe cooling section of the supply duct means, and exhaust means forwithdrawing air from said passage through the cooling section of thereceiving duct means.

7. The combination and arrangement of parts dened by claim 6, andfurther exhaust means communicating with the passage immediatelyadjacent the ends of the passage.

S. The combination and arrangement of parts defined.' by claim 6, anddamper adjusting mechanism oy which the dampers of any selected set maybe closed while the dampers or" the other sets are disposed in openposition.

9. The combination and arrangement of parts defined by claim 6; and, inaddition thereto, damper adjusting mechanism by which the' dampers ofany selected set may be closed While the dampers of the other sets aredisposed in open position, and indicating means designating the lengthof the heating Zone and the length of the cooling zone resulting fromeach damper adjustment.

10. The combination and arrangement of parts dened `by `claim 6; and, inaddition thereto, damper adjusting mechanism by which the dampers of anyselected set may be closed while the dampers of the other sets aredisposed in open position, said mechanism including an element that ismoved to different positions when the different sets of dampers areclosed, and a designation at each position indicating the length of theheating zone and the length of the cooling zone when said element is insaid position.

CARL F. MAYER.

References Cited in the file of this patent UNITED STATES PATENTS NumberNumber Name Date Dreffein Oct. 28, 1930 Hormel Mar. 12, 1935 Byron Oct.5, 1937 Byron Nov. l, 1938 Mayer Aug. 15, 1944 Barnett Oct. 2, 1945FGREIGN PATENTS Country Date Switzerland May 2, 1932

